Duncan continues to attract interest after an impressive campaign last season with Sassuolo.
Duncan spent five years with the Nerazzuri before joining Sampdoria in 2014.
According to Gazzetta dello Sport, the Ghanaian international remains hot property in the transfer market with Inter, who already have had a bid turned down, Fiorentina and Roma all reported to be keen.
But with Radja Nainggolan renewing, Roma slips out of the race leaving the San Siro and
Stadio Artemio Franchi side’s to rival each other for the Black Stars enforcer.
Fiorentina are also said to be eyeing the 24-year-old as the replacement for Matias Vecino, who joined Inter Milan last week.